Custom Code Highlighter Builder
Choose your own code highlight colors. Preview the theme and download its CSS and a sample HTML code card.
How do I make my own code color theme?
Paste code and choose a color for each part, such as keywords, strings and comments. Check the preview, then download the CSS and sample HTML. The tool does not run your code.
Your result
A little clarity, right here.
Start with your own content or load the example. Your result will appear here.
Three simple steps
How to use Custom Code Highlighter Builder
Choose your input and adjust the options.
Review the preview and run the tool.
Download the result and keep your original.
Common questions
Good to know
Understand the result.
Keep the original.
Is this tool free, and are my files uploaded?
This tool is free with no account required. The work happens in your browser. Your input and files are not sent to a processing server.
What are the limits and details?
Code cards support up to 300 lines and 160 columns. Fonts use local monospace fallbacks, so glyph appearance varies by device. Exports contain source text; remove secrets before sharing a card.
Limits: 500,000 characters per text field; files up to 20 MB each, 10 files and 50 MB total. Processing stops after 30 seconds.